The biodiesel fuel is a mixture of saturated and unsaturated carboxylic acids, along with glycerol, methanol, and water, as a result of the transesterification of animal or vegetable fats, utilizing potassium hydroxide as a catalyst. In addition, some of the potassium hydroxide is carried over into the biodiesel fuel. The biodiesel fuel is decanted and filtered from the byproducts and is in itself characteristic of a typical No. 2 diesel fuel. However, the remaining byproducts from the manufacturing process have sufficient heat value to warrant further processing for their use as a liquid fuel.
Although the byproduct mixture is combustible, it produces the following undesirable results if directly injected into a combustion chamber including:                (a) surface pitting caused by the potassium hydroxide component in the biodiesel byproducts creating surface pitting due to potassium deposition on components exposed to combustion temperatures;        (b) engine fouling and erratic combustion caused by the presence of palmitic acid in the fuel feedstock, due to its exceptionally high boiling point, resulting in incomplete combustion and soot formation; and        (c) wax buildup on components exposed to combustion temperatures, due to the presence of palmitic acid, with its exceptionally high boiling point.        